Abstract:We use 25 Sentinel-1A images covering Haihua island in Danzhou city, Hainan province from March 2020 to March 2022 to invert the spatial and temporal evolution of surface deformation of artificial island-reef using SBAS-InSAR and PS-InSAR techniques respectively. We analyze the deformation mechanism in key settlement areas and discuss the correlation between the island-reef surface deformation and sea level change. The results show that: 1)The spatial distribution and deformation trends of the two methods are highly consistent. 2)The average deformation rate in the SBAS-InSAR radar line of sight direction ranges from -14.69 to 6.96 mm/a, and the maximum cumulative subsidence is -37.18 mm. 3)The subsidence rate in the area near the outer sea is much higher than that in the area near the land area, and the deformation trend is affected by the ocean hydrodynamic disturbance and groundwater level change. There is a correlation between surface deformation with such deformation characteristics and sea level change.